Documentation

Open a minibuffer window with the given prompt and keymap
The third argument is an action to perform after the minibuffer
is opened such as move to the first occurence of a searched for
string. If you don't need this just supply return ()

withMinibufferGen proposal getHint prompt completer act: open a minibuffer
with prompt, and initial content proposal. Once a string s is obtained,
run act s. completer can be used to complete inputs by returning an
incrementally better match, and getHint can give an immediate feedback to the
user on the current input.